Work machines and/or vehicles may include various types of exhaust system emission components to regulate or reduce the amount of NOx compounds and other exhaust constituents released into the atmosphere. Diesel engine exhaust can include sulfur-containing compounds that may be trapped by exhaust system components, including NOx-adsorber catalysts. Over time, these trapped compounds may cause significant exhaust system sulfur contamination that can hamper the emission-controlling capability of the exhaust system.
To maintain exhaust system performance, sulfur contamination may be removed by periodic, rich regeneration. Rich regeneration may include operation of an engine with a rich air-to-fuel ratio at elevated temperatures. Removal of sulfur contamination by rich engine operation can, however, reduce the overall efficiency of an engine. Further, extended high temperature operation can cause a deterioration in the performance of exhaust system catalysts. Therefore, it may be useful to monitor exhaust system sulfur contamination and to desulfate only when necessary.
One method of monitoring exhaust system sulfur contamination is disclosed in U.S. Pat. No. 6,803,236, issued to Bailey on Apr. 12, 2004 (hereinafter the '236 patent). The method includes the use of multiple NOx sensors disposed at different locations within the exhaust system. The method further includes comparing the response time differentials of the multiple sensors to determine a level of sulfur compound contamination.
While the method of the '236 patent may provide an indication of exhaust system sulfur contamination, this method has several drawbacks. Particularly, the method requires multiple sensors. Further, the method may require multiple sensor types with different gas sensitivities and response times. While the method of the '236 patent may provide an indication of exhaust system sulfur contamination based on degradation of exhaust system catalyst performance, the method cannot provide a direct measure of exhaust gas sulfur-containing compounds.
The present disclosure is directed at overcoming one or more of the problems or disadvantages in the prior art.